ASA v9 why so many branches

[paul-d]

For the ASA 5545-x, software on chassis why are there so many branches of the V9 software and how do they differ?

[MHM Cisco World]

can you more elaborate ?

[paul-d]

Sure, as you can see below there are multiple branches of the V9 software, i wondered why.

[MHM Cisco World · Accepted solution]

https://www.cisco.com/c/en/us/td/docs/security/asa/compatibility/asamatrx.html

because each platform work with specific image ver. 
check asa compatibility above